Dateline: July, 2007, Issue 1

How do jurors respond to expert psychological testimony?

Two recent studies examined jurors' response to psychological testimony. One research study explored whether jurors focus on the content of the testimony or on the experts' credentials. The second research study explored jurors' expectations for the content of that testimony.

Research by McHenry (2002) found that jurors understand psychological expert testimony, and that they rely more on its helpfulness, intelligence, honesty, attractiveness and assertiveness than on the credentials of the psychological experts.

Jurors' expectations for the content of the psychological testimony differ from the expectations of judges and attorneys. Psychologists who participate as expert witnesses are often asked to provide ultimate opinions, that is, opinions that are legal decisions that are really the province of judges and juries such as opinions on insanity, child sexual abuse, competency to stand trial, rape, and violence risk assessments. Research by Vindice (1998) found that jurors almost always wanted ultimate opinion testimony, judges almost never wanted ultimate opinion testimony, and trial attorneys felt it to be appropriate sometimes.

Jurors understand psychological testimony and want ultimate opinions. Psychologists' credentials are less important than the content of the testimony.

Source McHenry, S. M. (2002). The response of mock jurors to psychological testimony presented in two adversarial trials conducted by practicing attorneys. Dissertation Abstracts International: Section B: The Sciences and Engineering, 62, p. 6025.

Source Vindice, V. (1998). Expert witness testimony by psychologists: A survey of judges, jurors and lawyers. Dissertation Abstracts International: Section B: The Sciences and Engineering, 58, p. 5659.